I. Field of the Invention
The present invention relates generally to a printer for selectively projecting photographic images onto a projection plane containing photographic paper. More particularly, the present invention relates to a high speed photographic package printer for producing a plurality of different sets or packages of photographs based on one or more negatives, wherein the improved package printer boasts an automatic paper-loading feature, dynamically controlled paper-slack loops, off-center printing, a rotational prism for creating 10".times.13" photographs, a 13-UP lens assembly including 12 wallet lenses and a single 5".times.7" retro-focus lens, an automatic diffusion plate cleaner, an improved dichroic lamp filtering arrangement, a focal plane shutter, bi-directional film movement, an improved film cleaner, and improved masking.
II. Discussion of the Prior Art
Photographic package printers have experienced proliferated use and widespread popularity due to their ability to generate custom made photographic packages consisting of selected photographs of varying size, shape, and style based on one or more negatives. Photographic package printers accomplish this by providing a lamphouse from which a beam of light is directed through photographic film onto a projection plane containing photographic paper for producing a print. In order to vary the shape and size of the particular prints, package printers are equipped with a plurality of movable lenses having varying magnification ratios so as to create a wide variety of exposures upon the photographic paper. By way of example and not limitation, package printers are commonly employed for processing the exposed photographic film from annual school photography sessions wherein each student within the school or class is photographed in any number of different poses using one or a plurality of different backdrops. The student may thereafter choose from among the various proofs generated during the photography session to order a custom package containing any number of different size or style photographs, such as wallet-size, 5".times.7,"8".times.10," and 10".times.13" photographs. However, the package printers of the prior art suffer from several substantial drawbacks both in terms of the speed of operation and print quality.
With specific regard to the speed of operation, the prior art package printers have several time limiting features which collectively restrict the ability of the package printers to operate at high speeds. One such drawback is that the prior art package printers typically require considerable time and energy to load the paper into the paper deck for subsequent exposure. Although several attempts have been made to automate the paper loading process, these efforts fail to provide a reliable means for guiding the paper during the loading stage such that significant system down time may be experienced to rectify the situation and reload the paper. For example, U.S. Pat. No. 5,181,066 to Ozawa et al. discloses a paper transporting device for a photographic printer which utilizes retractable bridge members to support the paper during the loading stage, a first pair of drive rollers for drawing the paper into the printer, and a second pair of drive rollers for propelling the paper to a processing section of the printer. U.S. Pat. No. 5,107,296 to Ozawa et al. discloses the use of retractable bridge members for controlling the transportation of the paper between a paper supply cartridge and a processing section. U.S. Pat. No. 4,961,093 also employs retractable bridge members so as to facilitate the loading of paper from a paper supply magazine into exposure apparatus and further to a take-up magazine. U.S. Pat. No. 4,655,583 to Kitai entails maintaining the traveling path of the photographic paper from a supply cartridge to nipping rollers in a straight manner by adjusting the height of an inner frame via elevator means. U.S. Pat. No. 4,566,784 to Nitsch discloses an apparatus for threading a new roll of paper into a photographic copier, comprising a retractable flap which, when disposed in the operative (guiding) position parallel to the paper, forms a passageway for threading the new roll of paper into the photographic copier. However, although the improvements offered in these references provide benefits over manual paper loading, their teachings are nonetheless flawed in that they merely provide guidance along a single surface of the paper, thereby allowing the paper to buckle and become fouled up during the loading process.
Another time limiting feature of the prior art package printers relates to the paper slack loops associated with the drive motors used to load and advance the photographic paper. Paper slack loops are essentially reservoirs containing a length of photographic paper which allows the paper to be advanced quickly into and out of an exposure area within the paper deck by factoring out the inertia of the paper supply spool. U.S. Pat. No. 5,181,066 to Ozawa et al. discloses a pair of loop sensors associated with each paper slack loop for detecting when the particular loop has exceeded a predetermined threshold. U.S. Pat. No. 5,107,296 to Ozawa et al. discloses a loop sensor for detecting a predetermined length of a first loop. U.S. Pat. No. 4,961,093 to Hicks also discloses the use of a pair of sensors for detecting when each particular paper slack loop exceeds a predetermined length. U.S. Pat. No. 5,159,385 to Imamura discloses a photolab system having a plurality of loop sensors for controlling the length of the paper within the respective paper loop reservoirs. The paper slack loop sensing arrangements within the above-identified references, however, are flawed in that they are not capable of detecting the actual length of the paper within each respective paper loop reservoirs but rather are merely capable of determining whether the particular paper loops have exceeded a predetermined limit or range. This is disadvantageous in terms of responsiveness in that a lag time exists between the instance that the sensors detect that the paper has exceeded the predetermined threshold and the time that the drive motors are activated to advance the paper, thereby limiting the overall speed at which the package printer can operate.
Another drawback stems from the manner in which 10".times.13" photographs are generated in prior art package printers. The traditional method for generating 10".times.13" photographs in package printers is illustrated in U.S. Pat. No. 5,162,843 to Clapp, wherein the photographic negative is physically rotated within the film deck in order to project a 10".times.13" image on the 10" wide paper. Although effective at producing the 10".times.13" photographs, this technique is particularly disadvantageous in that the mechanical turrets employed to rotate the negative are extremely bulky and heavy. The attendant bulk of the mechanical turret consumes a substantial amount of valuable space within the package printer, while the exorbitant weight limits the speed at which the negative can be rotated and causes substantial vibrations within the package printer which require lengthy settling time. The settling time and rotation time are additive such that the overall amount of time required to generate a 10".times.13" photograph is quite lengthy. Moreover, the mechanical turret can only support a limited amount of photographic film such that the film must be reloaded quite often. This increases the overall down time for the printer which, it will be appreciated, restricts the speed and throughput of these package printers. The mechanical turrets are also flawed in that the bearings are prone to wear out and become damaged through repeated rotation which, once again, leads to increased system down time for repair.
Another significant flaw in the prior art package printers is that they print on-center, that is, the negative is co-aligned with the approximate center of the photographic paper such that the image-bearing light projects in a directly vertical fashion from the negative to the approximate center of the photographic paper. U.S. Pat. No. 5,162,843 to Clapp, for example, discloses one such package printer which employs on-center printing. The main disadvantage of on-center printing is that it requires an extra step of advancing the photographic paper for the purpose of creating marking notches in the paper to indicate the end of each exposure and the end of each entire photographic session. Marking the paper in this fashion aids in the photograph development process in that the processing equipment can be equipped to interpret the various notches in order to automatically process, sort, and package the particular photographs within each photographic session. In order to properly mark each exposure and/or photographic session, the marking notches are preferably placed at or near the leading edge of each photographic exposure on the paper such that the processing components can accurately detect their occurrence. Typically, the marking notches are created through the use of one or more actuating cylinders disposed off-center to the negative. In that the printing is on-center, i.e. directly above the negative, the paper must be advanced after each exposure to accomplish the desired marking before advancing further to avail the next unexposed portion of paper. This is disadvantageous in that the paper must be stopped prior to performing the aforementioned marking process. It will be appreciated by those skilled in the art that the extra step of stopping to conduct punching activities consumes a substantial amount of valuable time.
Still other drawbacks with prior art package printers relate to the task of producing a plurality of differently sized photographs with a single exposure. More specifically, problems result due to the fact that this task is typically accomplished by situating a plurality of lenses having a variety of different magnification ratios on a single assembly within the lens deck. Each particular lens on the assembly has a corresponding focal point which requires the lens to be positioned a predetermined distance from the projection plane in order to produce the desired image on the photographic paper. Thus, each lens has a specific vertical height on the assembly which, in turn, causes the moment of inertia of the assembly to be far removed from the center of gravity of the assembly. This is disadvantageous in that removing the moment of inertia from the center of gravity causes the assembly to experience rocking during movement back and forth within the lens deck, thereby increasing the settling time between exposures. Still a further drawback with producing multiple images with a single exposure is that the ray traces from the various lenses tend to intersect if the number of lenses becomes too concentrated on the assembly. The intersection of ray traces is problematic in that it produces fouled or imperfect images on the photographic paper.
A still further drawback with the package printers of the prior art relates to the ability of the film to be translated during the operation of the package printer. To be more specific, the film within the package printers of the prior art are simply uni-directional, i.e. the film can only progress from the film supply spool to the film take-up spool. In this arrangement, then, the number of different composites which can be formed is very limited in that the various negatives cannot be switched back and forth into position over the lamp house. This effectively limits the range of possible composite photographs which can be accomplished with the package printers of the prior art. In order to overcome this deficiency, separate printers are specifically employed to create composite photographs using a plurality of different negatives. This is disadvantageous, however, in that the package printer and the composite printer will have different color emulsions and, therefore, resulting composites will not share the same color as the prints generated by the package printer. The need for a separate composite printer is also disadvantageous in terms of the time required to perform the custom printing and, moreover, the film and/or paper is subject to an increased risk of damage during the transportation to and from the composite printer.
Yet another drawback with the prior art package printers stems from the fact that the shutter assemblies are disposed above the focal plane. Positioning the shutter above the focal plane is problematic in that it requires a relatively large shutter opening and, therefore, a relatively large assembly to carry the shutter within the printer. The increased mass of the shutter assembly translates into decreased speed of operation in that there is more mass to move back and forth to effectuate a shutter operation. The increased mass of the shutter assembly also translates into increased settling time between shutter operations, thereby adversely affecting the reliability and operating speed of the package printer. Still another problem with positioning the shutter assembly above the focal plane is that interference may result between the shutter assembly and the lower lens assemblies within the lens deck.
Still another time limiting drawback with the package printers of the prior art pertains to the amount of energy consumed by the individual bulbs within the lamp house. To be more specific, the lamp house typically requires combining red, yellow, and green light in specific fashion to ensure for the proper exposure of the photographic paper. To accomplish this, the manufacturers of the lamp houses typically provide multiple (3 or 4) separate white light bulbs with each bulb equipped with a red, yellow, or green filter for creating the colored light. However, red is the predominant color required when creating the exposures on the photographic film and, as such, the underlying light bulb associated with the red filter is typically operated at a higher power than the light bulbs associated with the yellow and green filters. This presents a drawback in that each light bulb associated with a red filter will burn out at a higher frequency than the light bulbs used with the yellow and green filters due to the relatively large amount of power consumed by the red filtered light bulb, thereby increasing the amount of system down time when the burned out bulbs must be replaced.
Still other drawbacks exist in the prior art package printers with respect to print quality. First, the prior art package printers typically do not provide sufficient cleaning means for minimizing the amount of lint, dust, and other airborne contaminants from the surface of the film. For example, a typical film cleaning arrangement entails providing a pair of sticky rollers on the upstream or supply side of the photographic film in an effort to prepare the film for processing. However, such an arrangement is ineffective in eliminating all of the dust and related undesirables from the film so that the photographs may be marred or flawed. In the instance that such dust particles results on the film, it could translate into the ruination of an entire sitting which, as can be appreciated, results in lost profits due to wastefulness. At the very least, it will require manual touching up which, once again, adds to the overall time to create the photographs within each requested package.
Drawbacks also exist in the prior art package printers with regard to their ability to clean the diffusion plates used to equalize the light from the lamp house. For example, U.S. Pat. No. 5,181,066 to Ozawa et al. discloses a diffusion plate for diffusing and equalizing the light passing through the filter assembly of the light source wherein the diffusion plate must be cleaned manually between a predetermined number of sittings. This is flawed in that lint, dust, and other similar particles may come to rest on the diffusion plates such that spotted imperfections form on all the photographs being processed. This can be particularly damaging if the "floaters" are not discovered until after the processing of the exposed paper such that a large portion of the exposures must be repeated, consuming a substantial amount of system down time and resulting in large amounts of scrap and waste.
Yet another flaw in print quality resides in the masking used to crop the image bearing light beam to produce sharply delineated borders. U.S. Pat. No. 5,181,066 to Ozawa et al. discloses a variable mask including a length adjusting mask for adjusting the length of the exposure frame according to the print size, and a width adjusting mask for adjusting the width of the exposure frame according to the paper size and any border required in the print to be made. U.S. Pat. No. 5,287,141 to Yoshikawa also discloses a variable mask in an exposure room which masks the photographic paper in accordance with the particular print size. In similar fashion, U.S. Pat. No. 4,655,583 to Kitai discloses a trimming mask frame provided in conjunction with a press pan. However, these arrangements are incapable of adequately cropping the image bearing light beam to produce a well defined print border.
In light of the foregoing, therefore, a need exists for an improved high speed package printer which is capable of loading the photographic paper in an automatic fashion such that the paper will not be subject to buckling or become fouled in the paper transportation path. The improved high speed package printer should be capable of dynamically measuring the paper slack loops to ensure for the smooth and efficient operation of the paper drive motors. A need also exists for eliminating the need to advance the paper after each exposure to punch the paper at the leading edge of each exposure. The improved high speed package printer should also allow 10".times.13" photographs to be taken without the need for a rotating turret and should be capable of generating 12 wallet sized photographs and a single 5".times.7" photograph with a single exposure. The improved package printer should furthermore be capable of producing folio photographs comprising four different 4".times.5" photographic images, as well as automatically removing all dust particles and "floaters" from the diffusion plate so as to improve print quality. The improved high speed package printer should also be equipped with an improved lamp house filtering arrangement which reduces the degree to which the light bulbs associated with the red filter burn out so as to minimize system down time. The improved high speed package printer should also have an improved film cleaning arrangement for minimizing the amount of dust and related which are able to settle on the film, thereby reducing the amount of scrap and the amount of manual touching up required to salvage the marred photographs. The package printer should furthermore have an improved negative cropping arrangement for producing a sharply delineated print border. Lastly, the improved high speed package printer should have bi-directional film movement so as to increase the range of possibilities with respect to the various photographs included within a particular composite photograph.